Parallels today announced Parallels Desktop 9 , a major new version of the vitualization package for OS X. The new version boosts performance, adds cloud sync integration, makes more Mac features available to Windows, and adds Windows 8 usability features -- including the missing Start menu. The upgrade from Parallels Desktop 8 is available today for US $50; New uses will have to wait until September 5.

Parallels Desktop now runs Windows on Macs 40 percent faster than version 8, in terms of disk drive performance. Virtual machine shutdown is 25 percent faster, and suspending virtual machines is 20 percent faster. The company said that web browsing and 3D graphics used in games are 15 percent faster.

A new cloud optimization feature for iCloud, Dropbox, Google Drive, and SkyDrive prevents duplicate files on Mac and Windows, and synchronizes files on the Mac host and Windows guest.

Windows guest OS's get some additional OS X and Mac features. Two Mountain Lion features, Power Nap in certain notebooks, and the Dictionary lookup gesture (three-finger tap), now work in Windows running in a virtual machine. The Mac's Print-to-PDF feature now works for any Windows document.

Windows 8 gets some special treatment in Parallels Desktop 9, including the addition of the missing Start menu and Windows Start button in Windows 8. Metro apps can be used in a window instead of full screen -- something that isn't possible on a PC. Parallels Desktop 9 adds support for Windows 8.1 (Windows Blue) in a virtual machine. It also supports OS X Mavericks (OS X 9), which Apple will release this fall.

You can now use a Windows virtual machine that resides on a Thunderbolt or Firewire drive connected to the Mac. Additionally, when starting a virtual machine, Parallels Desktop 9 asks the user to whether to mount a connected Thunderbolt drive in OS X or a Windows virtual machine. (Previous versions ask the question for USB drives.)

Other general improvements include the ability to install a guest OS from a DVD, image file, or USB drive, a new security center for installing antivirus software in virtual machines, and the ability to search for virtual machine settings (similar to OS X's System Preferences).

Parallels Desktop 9 for Mac comes with a six-month subscription to the just-released Parallels Access for iPad, which enables iPad users to remote access Windows and Mac applications, with the look and feel of iOS apps. (See Parallels Access "app-ifies" Mac and Windows applications for iPads.)